Reciprocating sickles, while performing capably insofar as severing and mowing functions are concerned, give rise to vibrational problems as a result of the rapid directional changes incurred during reciprocation. The greater the mass of such sickles, the greater the vibration problems as a result of such abrupt starting and stopping action.
Thus, it has been known for many years that one way to dampen such vibrations is to have a pair of sickles on the same machine operating in mutually opposite directions so that the vibrational forces tending to be established by one of the sickles moving in one direction are counteracted by the forces generated by the other sickle moving in the other direction.
While various and sundry arrangements employing this basic principle have been utilized over the years, none has been entirely satisfactory for a number of reasons. In those assemblies in which a pair of sickles each covering about one-half the width of the header are used, there has been a problem at the center of the header where the two oppositely moving sickles come together during their inward strokes and separate during their outward strokes. In some cases, cutting in this area has been quite poor, and strips of unsevered materials have been left in the field along the center of the mower as a result of this problem.